Motor Control Device Voltage Drop Stabilization
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Solution Overview
Problem
Existing motor control devices for robots face challenges in maintaining stable operation during instantaneous voltage drops, leading to potential motor stoppages and reduced productivity, especially in environments with poor power supply, and they struggle to respond accurately to motor speed fluctuations without increasing processing costs.
Innovation Solution
A motor control device that includes a position command output mechanism, a voltage fluctuation detection system, and a limiter to adjust torque commands, allowing the motor to reduce speed and prevent windup phenomena during voltage drops, while using polynomial interpolation for precise position estimation without shortening the sampling cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor control device increases torque command to maintain motor operation during voltage drop, then motor operation is maintained, but windup phenomenon occurs causing unstable robot behavior
Solution Approach 1:
The control device detects voltage drops in advance and preemptively reduces the torque command before the voltage recovery occurs. This preliminary anti-action prevents the windup phenomenon from occurring in the first place, rather than trying to correct it after it has caused unstable robot behavior. The detector monitors voltage fluctuations and the controller adjusts torque commands proactively to counteract the potential harmful effects of voltage recovery.
2Reliability
If the motor control device stops the motor during voltage drop, then unstable behavior is prevented, but productivity decreases due to operation interruption
Solution Approach 1:
The control device dynamically adjusts the torque command based on real-time voltage conditions. During voltage drops, the controller reduces torque commands to prevent windup, and upon voltage recovery, it gradually increases torque back to normal levels. This dynamic adjustment allows the motor to continue operating throughout the voltage fluctuation without stopping, maintaining productivity while preventing unstable behavior through adaptive control parameters.
3Measurement precision
If the control system shortens the sampling cycle to improve position resolution, then position estimation precision increases, but processing cost and system complexity increase
Solution Approach 1:
The control device introduces an intermediary polynomial calculation mechanism that processes existing position data to generate high-resolution position estimates without requiring faster sampling. By fitting polynomial curves to the sampled position data, the system interpolates position values at arbitrary time points, achieving high position resolution while maintaining the original sampling cycle and avoiding the need for more complex or expensive hardware upgrades.
Data Source
AI summary
A motor control device may include a position command output means, a first subtraction means that calculates and outputs a position deviation, a position control means, a second subtraction means that calculates and outputs a position deviation, a speed control means that outputs a torque command, a limiter limits the level of the torque command, a motor drive means, and a voltage fluctuation detection means. When the voltage fluctuation detection means detects that the voltage of said power source has dropped below a predetermined reference level, either the position command output means varies the position command so as to reduce the rotational speed of the motor and/or said position control means limits said speed command to be output.